(1) Field of the Invention
This invention relates to a treatment device for developing films, such as oxide film, applied to semiconductor materials, such as silicon wafers, glass photomasks or the like.
(2) Description of the Prior Art
In the production of semiconductor circuits, semiconductor wafers consisted of silicon, for example, are subjected to the application thereto of film, such as oxide film, and the film on the wafer is then subjected to etching treatment for the purpose of selectively osmosing a N- or P-type diffusion material into the surface. In order to form a pattern of circuit, a photosensitive liquid (photo-hardening type photoresist) is film-like coated on a predetermined portion or portions of the wafer surface, and then the baking and developing treatments are performed.
As the developing treatment devices of this kind, there have hitherto been known a liquid blowing-up type device, a liquid spraying type device and a liquid spreading type device. The liquid blowing-up type device is, as shown in FIG. 6, constituted basically by a cup-shaped basin 10 having an inlet passage 11 for etching liquid at its lower portion and a chuck 20 provided above the basin 10 for holding a wafer S by pneumatic attraction. The passage 11 of the basin is connected to a pipe 12 for feeding the treatment liquid. An upper portion 13 of the basin is circular in shape and the liquid flows out over the upper portion of the basin. The lower portion of the basin 10 is provided on its outer periphery with a cylindrical guide 14 which serves as a guide for the flow of liquid.
The chuck 20 is vertically supported and a passage 21 is provided to extend along its center axis, and the passage is communicated at its upper end with a vacuum conduit 22. The conduit 22 has a pressure sensor 23 and a valve 24 which has an inlet pipe 25 for nitrogen gas and a pipe 26 for communication with a vacuum device. If desired, the chuck 20 is arranged so that it is rotatably driven by an electric motor 27 through a belt 28. There are further provided a holder 29 for enclosing the chuck and gas inlet port 30 formed in its appropriate position. The film on the wafer supported by the chuck 20 is developed with developing liquid blown up against the same.
The liquid spraying type device is diagrammatically shown in FIG. 7 and is arranged so that developing liquid is atomized by and sprayed from a nozzle 31 onto the wafer S for development. The liquid spreading type device is also shown in FIG. 8 in a diagrammatic illustration and is arranged so that an appropriate amount of developing liquid is dropped onto the center of the wafer, the dropped liquid then flowing thereon towards the peripheral edge and being held on the wafer surface under the action of surface tension.
These conventional devices described above have such drawbacks and problems as will be pointed out below. The developing liquid has, as its principal component, tetramethyl choline, or tetramethyl ammonium and hydroxide, or so, and such a developing liquid is disposed of at every developing treatment. In the liquid blowing-up type device, therefore, there is a problem that the continuous flow and blowing-up of developing liquid will result in a large or wasteful consumption thereof and in an increase in the production cost of the wafers. In the liquid spraying type device, there is another problem that the size of the liquid particles is often larger than that of the pattern to be developed, and this will result in an uneven development and in a decrease in the resolving power. In the liquid spreading type device, there is a further problem that the central area of the wafer to which developing liquid is dropped is developed by fresh liquid under a certain pressure and the liquid becomes degraded while flowing towards the periphery of the wafer and the reaction pressure and velocity vary in the central and peripheral areas of the wafer, which results in an uneven development.